We are using CanvasJS for an XYY line chart. We are allowing the software users choose to have the chart display with CanvasJS automatic calculated values, or to set their own Minimum, Maximum and Interval values for each of the Y Axes. Any combination of those 6 options are possible at any time. With User supplied Minimum and Maximum values all seems to be OK, the chart is rendering as expected. When we set Interval a Y or Y2 axis interval value, as shown below: